Rust-preventive compositions



Patented Aug. 24, 1954 RUST-PREVEN TIV E COMPOSITIONS John D. Spivack,Bayonne, N. J., assignor to Tide Water Associated Oil Company, Bayonne,N. J a corporation of Delaware No Drawing. Application September 13,1951, Serial No. 246,513

14; Claims.

The present invention relates to rust-inhibiting compositons and,particularly, to compositions adapted for prevention of rusting ofcorrodible metals upon exposure thereof to corrosioninducing conditions.

Broadly speaking, the compositions embodied herein comprise a suitablevehicle and a small amount, suflicient to impart rust-preventivecharacteristics thereto, of a novel di-nitrogencontaining dicarboxylicacid as described more fully hereinafter.

With reference to the vehicle component of the compositions embodiedherein, materials may be employed which, though otherwise suitable for aparticular usage, may require improvement with respect to their abilityto prevent rusting of metals in contact therewith and exposed torustinducing conditions such as highly humid atmospheres. For purposesof illustration but not limitation, the vehicle may be of the volatileor non-volatile type of hydrocarbons, such as mineral oils and fractionsthereof, examples of which include hydrocarbon lubricating oils,greases, petrolatum, and the like. Thus, and depending on intended usageof the novel compositions, the vehicle component thereof may be amaterial having properties suitable for such usage except for desiredimprovement in rust-preventive characteristics and is capable of beingimproved therein by a rust-inhibiting agent as embodied herein. Hence,compositions embodied herein include those contemplated for use ashydraulic fluids, slushing compositions, lubricants, and the like and,in particular, liquid compositions contemplated for use in lubricationof turbines exposed to severe rust-inducive conditions.

The di-nitrogen-containing dicarboxylic acids embodied for use herein asthe rust-inhibiting component, are dimer products definable asdi(N-carboxyalkylalkanamides) and described in my copending applicationSerial No. 231,891, filed June 15, 1951, now U. S. Patent No. 2,644,826,issued July 7, 1953. As set forth in said copending application, thedisclosure of which is incorporated by reference herein, a method bywhich di(N-carboxyalkyl alkanamides) contemplated for use herein maysuitably be prepared comprises subjecting a(N-alkanoyDiminodialkanoylnitrile to basic hydrolysis in the presence ofa suitable hydroxylic liquid under ammonia-liberating reactionconditions. In such preparation of the novel rust-inhibitingalkanamides, the (N-alkanoyl)iminodialkanoylnitrile employed as thereactant may vary over a wide range of carbon atom content with respectto the alkanoyl radical in the (N-alkanoyl) grouping and, as usedherein, the term alkanoyl is intended to include the acyl residue offatty acids both of the saturated and unsaturated type. For purposes ofillustration and not limitation, (N-alkanoyl)iminodialkanoylnitrilesthat may be employed for preparation of the novel rust-inhibiting agentmay contain, as the alkanoyl radical in the (N -alkanoyl) grouping, anacyl residue of a long chain fatty acid, e. g. containing about six toabout thirty carbon atoms, such as the acyl residue from stearic acid,oleic acid, behenic acid, caprylic acid, and the like. Examples of such(N-alkanoyl) iminodialkanoylnitriles include the(N-alkanoyl)iminodipropionitriles and, more specifically, nitriles suchas (N-stearoyl) iminodipropionitrile, (N lauroyl)iminodipropionitrile,(N behenoyl)iminodipropionitrile, (N capryloyl) iminodipropionitrile,and the like.

The di(N-carboxyalkyl alkanamides) possess such highly efiectiverust-preventive characteristics that usually only a small amount thereofis required for preparation of the compositions embodied herein. Hence,highly effective rustpreventive compositions may be prepared comprisingthe vehicle in major amount by weight and a minor amount of therust-inhibiting agent. The actual amount. of rust-inhibiting agentemployed may be varied depending on factors such as the desired degreeof improvement in rustpreventive characteristics, solubilitycharacteristics of the rust-inihibiting agents in the particular vehicleemployed, and the like but, for most purposes, the rust-inhibiting agentis employed in about 0.005 to about 1% by Weight based on the weight ofthe composition. Although the compositions embodied herein comprise, inboard aspect, a vehicle capable of being imparted with rust-preventiveproperties by having dissolved therein a rust-inhibitingdi(N-carboxyalkyl alkanamide), an embodiment relates to suchcompositions which also contain a solubilizing agent for thedi(N-carboxyalkyl alkanamides), For example, certain of thedi(N-carboxyalkyl alkanamides) are slightly, if at all, soluble incertain vehicles and, in instances wherein it is desired to preparerust-inhibiting solutions containing the aforedescribed alkanamides insuch vehicles, a solubilizing agent that is compatible with the vehicleand functions as a solubilizing agent for the alkanamide is employed. Inillustration of such an embodiment, certain of the di(N-carboxyalkylalkanamides) possess limited solubility in paraflinic-type oils, such ashighly refined conventional solvent extracted lubricating oils usefulfor lubrication of turbines, and in the use thereof for preparation ofcompositions as embodied herein a solubilizing agent for the alkanamideis also incorporated in the composition. Illustrations of suitablesolubilizing agents for such usage includes oil-soluble alkylamines suchas the amylamines, octadecylamines, prinhiary long chain branched alkylamines, and the In order to further describe the invention, thefollowing examples set forth compositions illustrative but notlimitative of this invention; and included therein are the performancecharacteristics of the compositions when subjected to the severerust-inducing conditions of the corrosion test described in NavyDepartment specification pamphlet 14-0-15, symbol 2190-1, as amendedMarch 1, 1948, relating to specifications for steam turbine lubricants.Briefly, the test described therein provides that polished cylindricalsteel specimens be partially immersed for 48 hours in a bath maintainedat 140 F. and composed of 300 ml. of the lubricant under test and 30 ml.of synthetic sea water. In order to pass that test, the immersedportions of the steel specimens must show no corrosion at the completionof the 48-hour period. For purposes of completeness, the followingprocedure is also set forth illustrative of a suitable method forpreparation of the di(N-carboxyalkylalkanamides) employed in preparationof the rust-inhibiting agents used in the compositions of the exampleshereinafter set forth.

PREPARATIONS OF DI (N-CARBOXYETHYLALKANAMIDES) A. Preparation ofdz(N-carbioozyethylstearamide) Nine grams (0.023 mole) of (N-stearoyl)iminodipropionitrile were introduced into a 300 ml. round-bottom flaskcontaining a solution of 15 grams of potassium hydroxide in 150 cc. ofnpropanol. The flask was connected to a reflux condenser through anadapter providing for sweeping the inside of the flask with dry nitrogenand the condenser connected to an absorber (standard aqueous H2304) toabsorb liberated ammonia. The reaction mixture was maintained at refluxtemperature of the propanol until substantially two moles of ammoniawere absorbed for each mole of nitrile reacted. The time of reaction was1% hours and the amount of ammonia absorbed was 42.9 millimoles. Therefluxed product was a homogeneous solution containing the potassiumsalts of di(N-carboxyethylstearamide). The solution was poured into 400cc. of water and the resultant solution acidified with hydrochloric acidto convert the potassium salts to the free acids which precipitated as awhite gelatinous mass and crystallized from acetone. The crystallizedproduct had a melting point of 119-120" 0., possessed two carboxylgroups per molecule evidenced by neutralization equivalent points of 708and 352 upon determination thereof electrometrically indimethylformamide and possessed two nitrogen atoms per molecule. Thedi-nitrogencontaining dicarboxylic acid product thus produced and hereindesignated di(N-carboxyethylstearamide) had an empirical formula ofCaHsoOsNz and carbon, hydrogen and nitrogen content as shown in thefollowing tabulation which also includes corresponding theoreticalvalues for the di(N -carboxyethylstearamide) derivative from(N-stearoyl) iminodipropionitrile.

that was filtered, air dried Theoretical Values for Reaction Productdi(N-carboxyethyl stearamide) Carbon Content 71.16%; 71.34% 71.11%Hydrogen Content i 11.60%; 1l.38% 11.37% Nitrogen Content 4.46%; 4.63%3.95%. Neutralization Equiva1ent- 708 and 352 709.1 and 354.6.

B. Preparation 0 di(N-carbomyethyllauramide) By use of a procedure asdescribed hereinbefore using a 0.43 Normal ethylene glycol-KOI-Isolution instead of n-p-ropanol in the reaction, the correspondingderivative from (N lauroyD- iminodipropionitrile was prepared, saidderivative being termed di(N-carboxyethyllauramide) and characterized bybeing a white crystalling material having a melting point of 109-111 C.

Example I A solution was prepared comprising (by weight) 0.05% ofdi(N-carboxyethyllauramide) and 0.03% of diamylamine as a solubilizingagent in a light turbine oil prepared by solvent (furfural) extractionof a predominantly paraflinic distillate lube and which oil per se issubstantially ineffective in protecting metals against rusting under theconditions of the aforedescribed corrosion test. Another composition wasprepared comprising by weight 0.08% of di(N-carboxyethyllauramide) and0.048% of di-n-amylamine in the aforesaid light turbine oil.

Both of the compositions of this example were subjected to theaforedescribed corrosion test and performed efiectively asrust-preventive compositions in the presence of synthetic sea water asnoevidence of corrosion on the polished steel specimen had occurred inthe 48-hour immersion test.

Example II A solution was prepared comprising (by weight) 0.03% ofdi(N-carboxyethylstearamide) and 0.036% of Alkylamine JM as asolubilizing agent in the aforedescribed light turbine oil. AlkylamineJM is a product marketed by the Rohm and Haas Company of Philadelphia,Pa, and understood to comprise an 18 carbon atom primary branched chainalkylamine which, when used alone in a turbine oil as aforesaid andsubjected to the conditions of the aforedescribed test, fails tosubstantially (if at all) improve the rust-preventive characteristics ofthe turbine oil.

Another solution was prepared comprising (by weight) 0.05% ofdi(N-carboxyethylstearamide) and 0.06% of Alkylamine JM in theaforedescribed turbine oil.

Both of the compositions of this example, upon being subjected to theconditions of the aforedescribed corrosion test, protected the metalspecimens against corrosion during the 48-hour exposure.

Although the present invention has been described in conjunction withcertain preferred embodiments thereof, those skilled. in the art willreadily recognize that variations and modifications can be made.Moreover, it should be understood that compositions, as embodied hereinand containing the aforedescribed rust-inhibiting agent, may alsocontain additional ingredients for imparting other desired properties tothe composition. In illustration, the compositions may contain ananti-oxidant, such as an aromatic amine anti-oxidant, e. g. phenyl alphanaphthylamine,

antifoam agents of the viscosity index improvers, e. g. polyacrylates,silicone type, and the like.

I claim:

1. A composition comprising a substantially non-corrosive vehicle inmajor amount based on the weight of the composition and a small amount,sufiicient to impart rust-inhibiting properties, of a rust-inhibitingdi(N-carboxyalkylalkanamide) in which the alkanoyl radical of thealkanamide grouping is an alkanoyl residue of a long chain fatty acid.

2. A composition, as defined in claim 1, wherein the vehicle is ahydrocarbon.

3. A composition, as defined in claim 1, wherein the vehicle is amineral oil.

4. A composition, as defined in claim 1, wherein the alkanamide is adi(N-carboxyethylalkanamide).

5. A composition, as defined in claim 1, wherein the alkanamide ischaracterized by containing, in the alkanoyl radical of the alkanamidegrouping, an alkanoyl residue of a fatty acid of about six to aboutthirty carbon atoms.

6. A composition, as defined in claim 1, which in addition contains asolubilizing agent for the alkanamide.

7. A composition comprising a hydrocarbon vehicle in major amount, basedon the weight of the composition, having dissolved therein a smallamount, sufiicient to impart rust-preventive characteristics, of arust-preventive di(N-carboxyethylalkanamide) in which the alkanoylradical of the alkanamide grouping is an alkanoyl residue of a longchain fatty acid.

8. A composition, as defined in claim '7, wherein the alkanamidecontains, as the alkanoyl radical of the alkanamide grouping, analkanoyl residue of a fatty acid of about six to about thirty carbonatoms.

9. A composition, as defined in claim 7, which, in addition, contains anoil-soluble solubilizing agent for the alkanamide.

10. A composition, as defined in claim 9, wherein the solubilizin agentis a member from the group consisting of oil-soluble primary alkylaminesand oil-soluble secondary alkylamines.

11. A composition, as defined in claim 7, wherein the vehicle is amineral oil of turbine lubricating grade.

12. A composition comprising a mineral oil of lubricating grade in majoramount based on the weight of the composition having dissolved therein asmall amount, sufiicient to impart rust-preventive characteristics tosaid composition, of a di(Nwarboxyalkylalkanamide) from the groupconsisting of di(N-carboxyethyl stearamide) and di(N-carboxyethyllauramide) 13. A composition, as defined in claim 12, which, inaddition, contains an oil-soluble alkylamine as a solubilizin agent forsaid di(N-carboxyalkylalkanamide) 14. A composition, as defined in claim12, wherein the mineral oil is a solvent refined mineral oil of turbinelubricating grade.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,388,132 Fischer Oct. 30, 1945 1 2,403,067 Fischer July 2,1946

1. A COMPOSITION COMPRISING A SUBSTANTIALLY NON-CORROSIVE VEHICLE INMAJOR AMOUNT BASED ON THE WEIGHT OF THE COMPOSITION AND A SMALL AMOUNT,SUFFICIENT TO IMPART RUST-INHIBITING PROPERTIES, OF A RUST-INHIBITINGDI(N-CARBOXYALKYLALKANAMIDE) IN WHICH THE ALKANOYL RADIACAL OF THEALKANAMIDE GROPING IS AN ALKANOYL RESIDUE OF A LONG CHAIN FATTY ACID.